Drawing-board



G. H. GILCHRIST.

DRAWING BOARD. APPLICATION FILED 0c r.20.-|919.

Patented J 11116 7,1921.

I IVl/E/V TUE EEUREEH, EILEHIf/ET I ain, a resident GEORGE: nnean GILGERIST, or orrawii, ONTARIO, CANADA,

nanwmegsomtn.

issacae,

spe'ci'licationiof I iett'ers Patent;

Patented June 7,1921.

Application filedOctober 20, 1919. Serial No. 331,894.

T 0 all whom it may concern Be it known that I, GEORGE HAGAR GIL- CHRIST, a subject of the King of Great Britof the city of Ottawa, Province of Ontario, Dominion-of Canada, have invented certain new and useful Improvements in Drawing-Boards, of which the following is a specification.

This invention relates to improvements in drawing boards, and the objects of the invention are to permit of the drawing board being rotated through any desired angle in a horizontal plane, to provide means for a visional indication of the angular displacement of the board, to permit of a T-square ruler or other drawing instrument, being slidablyv adjusted so that parallel lines can be readily drawn to permit of the instrument and the guides, supporting the said instrument, being graduated, so that lines of predetermined length can be drawn and spaced apart as desired.

With the above and other objects in view, the invention consists essentially of the improved construction particularly described and set forth in the following specification and accompanying drawings forming part of the same. 7

In the drawings:

Figure 1 is a perspective View of the improved drawing table.

Fig. 2 is a longitudinal section of the same.

'Like characters of reference refer to like parts in the several figures.

Referring to the drawings, A represents a table comprising a top 10 supported by legs 11, the top being provided with lateral guide members 12 which may be graduated on theupper face.

The top 10 isprovided at a central point with a bearing 13 designed to rotatably engage with the stub spindle or pin 14 carried by the pulley 15 which is rigidly attached to the board 16, so that the board and pulley are designed toi'be simultaneously rotated in a horizontal plane on the stub spindle or pin 14, as a pivot.

To eliminate friction between the pulley 15 and the top 10 0f the table, I provide a plurality of rollers 17 designed to engage with the race 18, and in this way vibration of the board and pulley during rotation is eliminated and the turning of the table can be very readily accomplished.

At one side of the table 10 a pulley 19 is rotatably mounted, and a strap 20 of a material, which does not possess stretch,

engageswith the pulley 19 and 15, this strap 7 being of the endless type, and having graduated or otherwise marked delineated on the outer face angles which the strap subtends at the center of the large pulley 15.

So that these markings on the strap 20 will be readily discernible, I provide a reflector in the form of a mirror or like device 21, which will be located adjacent to the strap, and disposed in such a manner that it may be readily observed, and by looking into this mirror or reflector member, the graduations on the strap directlyopposite the mirror will be readily seen, so that the operator will at all times know exactly the angular displacement of the board 16.

Superimposed on the board 16 is a T- square 22, the transverse arms 23 of which embrace the outer face of the lateral guides 12, and the upper face of the T-square 22 is raduated preferably in inches.

s the guides 12 are graduated on the upper face, then by moving the T-square 22, the distance between parallel lines can be readily gaged,'and since the T-square is the strap is reflected in the mirror.

This board is of an extremely simple construction and there are no parts liable to get out of repair.

As many changes could be made in the above construction, and many apparently widely different embodiments of my invention, within the scope of the claim, constructed without departing from the spirit or scope thereof, it is intended that all matter contained in the accompanying specifi-, cation and drawings shall be interpreted asv illustrative and not in a limiting sense.

What I claim as my invention is:

A drawing board comprising a table having end guide members, a drawing board, a pulley attached to the drawing board, a pin carried by the pulley, a bearing centrally located in the top of the table and designed by the graduated portion of the strap in to receive the pin, anti-friction rollers loefront of the reflector will be reflected to tween the pulley and the table, a second pulshow the angle of rotation of the drawing 10 ley, an endless strap engaging the two pulboard, as and for the purposespecified.

5 leys and provided on the outer face with In Witness whereof I have hereunto set graduations, and a reflector on the table my hand. adjacent to the outer face of the strap where- GEORGE HAGAR GILCHRIST. 

